Uranyl nitrate complexes of camphene-derived organophosphorus ligands, and the X-ray crystal structure of [UO 2(NO 3) 2(RPO3Me 2) 2] (R=endo-8-camphanyl)

Abstract

endo-8-Camphanylphosphinic acid [(2,2-dimethylbicyclo [2.2.1] hept-3-ylmethyl)phosphinic acid] camPO 2H 2 1 is readily oxidised to the corresponding phosphonic acid camPO 3H 2 2, the preferred reagent being SO 2 in refluxing isopropanol. Methylation of the phosphonic acid 1 with diazomethane yields the methyl ester camPO 3Me 2 4. Oxidative chlorination of camPO 2H 2 with SOCl 2 produces the phosphonic dichloride camP(O)Cl 2 3, which gives the tertiary phosphine oxide camP(O)Ph 2 5 on reaction with PhMgBr. The phosphonate ester 4 and phosphine oxide 5 readily form complexes 6 and 7 respectively with uranyl nitrate. The phosphonate complex 6 has been subjected to a single-crystal X-ray diffraction study. The structure determination was not straightforward, largely as a result of the combination of a dominant scattering atom (uranium) and substantial disorder of the camphanyl groups.